From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- Documentation/leds/leds-lp5521.rst | 115 +++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 Documentation/leds/leds-lp5521.rst (limited to 'Documentation/leds/leds-lp5521.rst') diff --git a/Documentation/leds/leds-lp5521.rst b/Documentation/leds/leds-lp5521.rst new file mode 100644 index 000000000..0432615b0 --- /dev/null +++ b/Documentation/leds/leds-lp5521.rst @@ -0,0 +1,115 @@ +======================== +Kernel driver for lp5521 +======================== + +* National Semiconductor LP5521 led driver chip +* Datasheet: http://www.national.com/pf/LP/LP5521.html + +Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo + +Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) + +Description +----------- + +LP5521 can drive up to 3 channels. Leds can be controlled directly via +the led class control interface. Channels have generic names: +lp5521:channelx, where x is 0 .. 2 + +All three channels can be also controlled using the engine micro programs. +More details of the instructions can be found from the public data sheet. + +LP5521 has the internal program memory for running various LED patterns. +There are two ways to run LED patterns. + +1) Legacy interface - enginex_mode and enginex_load + Control interface for the engines: + + x is 1 .. 3 + + enginex_mode: + disabled, load, run + enginex_load: + store program (visible only in engine load mode) + + Example (start to blink the channel 2 led):: + + cd /sys/class/leds/lp5521:channel2/device + echo "load" > engine3_mode + echo "037f4d0003ff6000" > engine3_load + echo "run" > engine3_mode + + To stop the engine:: + + echo "disabled" > engine3_mode + +2) Firmware interface - LP55xx common interface + +For the details, please refer to 'firmware' section in leds-lp55xx.txt + +sysfs contains a selftest entry. + +The test communicates with the chip and checks that +the clock mode is automatically set to the requested one. + +Each channel has its own led current settings. + +- /sys/class/leds/lp5521:channel0/led_current - RW +- /sys/class/leds/lp5521:channel0/max_current - RO + +Format: 10x mA i.e 10 means 1.0 mA + +example platform data:: + + static struct lp55xx_led_config lp5521_led_config[] = { + { + .name = "red", + .chan_nr = 0, + .led_current = 50, + .max_current = 130, + }, { + .name = "green", + .chan_nr = 1, + .led_current = 0, + .max_current = 130, + }, { + .name = "blue", + .chan_nr = 2, + .led_current = 0, + .max_current = 130, + } + }; + + static int lp5521_setup(void) + { + /* setup HW resources */ + } + + static void lp5521_release(void) + { + /* Release HW resources */ + } + + static void lp5521_enable(bool state) + { + /* Control of chip enable signal */ + } + + static struct lp55xx_platform_data lp5521_platform_data = { + .led_config = lp5521_led_config, + .num_channels = ARRAY_SIZE(lp5521_led_config), + .clock_mode = LP55XX_CLOCK_EXT, + .setup_resources = lp5521_setup, + .release_resources = lp5521_release, + .enable = lp5521_enable, + }; + +Note: + chan_nr can have values between 0 and 2. + The name of each channel can be configurable. + If the name field is not defined, the default name will be set to 'xxxx:channelN' + (XXXX : pdata->label or i2c client name, N : channel number) + + +If the current is set to 0 in the platform data, that channel is +disabled and it is not visible in the sysfs. -- cgit v1.2.3